Sewing machine



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J. KlEwlcz SEWING MACHINE Filed April 1:5

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Patented Sept. 11, 1923.

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JOHN KIEWICZ, or` BOSTON, MASSACHUSETTS, ASSIGNOR TO THE Renon BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION or MAINE.

SEWING MACHINE.

Application filed April 13, 1922.

To all whom it may concern.

Be it known that JOHN Kmwvicz, a citizen of the United States, and resident of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement 1n Sewing Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to Sewing machines of that type in which the under thread mechanism is in the form of a rotary hook constructed to take a loop of the upper or needle thread and cast it about a bobbincase containing a bobbin carrying the under thread thereby to lock the needle thread with the bobbin thread.

In sewing machines of this type the bobbin case is usually situated within the rotary hook and is held from rotation by means of a suitable arm or finger, there being suiiicient clearance between the bobbin case and the hook to enable the needle thread loop to pass freely around the bobbin case. The finger above referred to is employed to prevent the bobbin case from rotation and it normally rests against a shoulder formed on the bobbin case for this purpose. 1n order to enable the loop of needle thread to be carried freely around the bobbin case it is desirable to separate the shoulder from the finger at the time when the loop of needle thread is passing the finger so as to provide sufficient clearance and to prevent the needle thread from being caught between engaging parts with the consequent liability of having the thread broken.

My invention has for its object to provide means for controlling the bobbin case so as to provide the necessary clearance to permit the loop of needle thread to freely pass over said bobbin case without being interfered with by the means for holding the bobbin case from rotation.

In Order to give an understanding of the invention I have illustrated in the drawings a selected embodiment thereof which will` now be described after which the novel features will be pointed out inv the appended claims.

Fig. 1 is a side view Of a two-thread sewing machine of known construction.

`Fig. 2 is an under side view of the bed of the sewing machine illustrating the mech- Selial No. 552,214.

anism for shifting the position of the bobbin case.

Figs. 3 and 1- are sectional views on the line 3-3, Fig. 1 showing the parts in different position. y

Fig. 5 is a sectional view through. the driving shaft for the hook.

I'Fig.` 6 is a fragmentary view of the bobibin case showing the positioning fingers.

glVhile my invention is capable of being used with various sewing machines I have herein chosen to illustrate it as embodied in a buttonhole sewing machine of the type shown in United States Patents No. 749,776, Jan. 19, 190A, No. 1,088,652, Feb. 2A, 191A, and No. 1,402,073, J an. 3, 1922, and my copending application for United States Patent Ser. No. 552,926, filed April 15th, 1922.

The machine shown in the drawings is formed with a bed plate 1 on which the work is clamped by suitable work clamps 2 and which sustains an overhanging arm 3 supporting suitable bearings 1n which reciproeates a needle bar f1 carrying the usual needle 5. Situated beneath the bed plate is a bobbin case G carrying a bobbin which supplies the under thread, and a rotary hook 7 adapted to talre each loop of needle thread and carry it about the bobbin case all as usual in sewing machines employing a rotary hook and bobbin case.

. rfhe hook 7 is formed on a rotating member 8 which is connected and driven by a shaft 9, and this shaft is connected by gearing 10 with a cross shaft 11 which in turn is connectedby gears 12 with a drive shaft 13, the latter having a pulley 14C thereon by which it may be Operated.

rlhe needle bar 4L is also reciprocated by suitable mechanism driven from the vdrive shaft 13 all as usual in sewing machines of this type; The rotary member 8 is provided with a chamber 15 in which, the bobbin case G is partially received.

The parts thus far described are or may be all as usual in sewing machines of this type and constitute no part of my present invention and in the operation Of t-he machine the needle 5 makes its penetrating thrust and as the needle begins to rise it throws out a loop of needle thread which is caught by the hook 7 and which is carried around the bobbin case 6 by the rotation of the hook, thus interlocking the needle thread with the bobbin thread.

nose as itis being shed from the bobbin case as shown in Fig. 4, I have provided means for withdrawing and separating the arm 23 from the nose at the timethat the l loop y'18 is about to pass said nose. For this purpose the arm 23 is fast on a roclr shaft 22 which is journalled in bearings 21 formed on the bed land saidV rock shaft has fast thereon an. arm 25 which engages a cam -member 26 fast on the shaft 13 and having two cam projections 27.y said arm 25 being held against the cam by the spring 28.

When the arm 25 rests against the concen-v tric portion of the cam 26 the arm 23 engages the nose 24 of the bobbin case and holds the latter from rotation. y

The bobbin case is provided with a notch 16,' in which is received the end of a stationary finger 17 that is rigid with the bed 1.' The notch 16 is somewhat wider than the finger 17 and is so disposed with relation to said fin ger that when the arm 23 is engaging the nose 24, as shown in` Fig. 3, the end of the finger 17 will be situated centrally of the notch and separated from both sides thereof. When in this position there willbe a clear,- ance space around the finger 17, as shown best in Fig. 6, so that the loo 18 of needle thread can readily pass the nger without being caught between the finger and the walls of the notch.

r In the operation of the sewing machine `the parts will be in the position shown in Fig. 3 as the needle makes its penetrating thrust and as the hook 7 takes the loop of needle, thread and begins to carry it aroun the bobbin case.

When the parts are in the position shown in Fig. 3 there is clearance around the Apositioning finger 17 so that the loop 18v of needle thread can pass freely about'the finger and between the latter and the bobbin case, asshown in Fig. After the loop 18'passes the finger 17 when it is about to Ipass the nose 24 a cam projection 27 engages the arm 25 and lifts the` arm 23 from the nose, as shown in Fig. 4, thus providing clearance for the loop 18 at this point. hen the arm 23 is raised from the nose 24 the positioning finger 17 prevents rotary movement of the bobbin case by its engagement with the shoulder 20. i

It will be understood, of course, that the shaft 13 operates in timed relation with the shaft 9 and that the cam projections 27 are positioned to provide necessary clearance between the finger 23 and the nose 24 at the proper point in the cycle of operations.

In the present embodiment of the invention the shaft 9 rotates twice for each rota tion of the driving shaft 13 and consequently the member 26 will have two cam projections 27 thereon.

I claim.

1. In a sewing machine, the combination with a vertically-reciprocating needle, of a driving shaft from which the needle is operated, a bobbin case having a nose and aA shoulder, a hook-operating shaft geared to the driving shaft, a rotary-hook connected to and driven by said hook-operating shaft and adapted to take a loop of needle thread'and cast it about the bobbin case, a pivoted finger normally engaging the nose and Vpreventing rotation of the bobbin case, a cam for actuating said finger, saidl cam being fast on the driving shaft and having a relatively long low portion which holds the finger in operative position in engagement with said nose, and a relatively short high portion which functions to separate said finger from the nose to allow a loop of needle thread to pass, and a stationary positioning finger co-operating with said shoulder to prevent rotation of the "bobbin case when the pivoted finger is withdrawn from the nose.

2. In a sewing machine, the combination withl a bed plate, of a verticallyreciprocating needle, a driving shaft situated beneath the bed plate and by which the needle'is op-y erated, a bobbin case having a nose and a shoulder, a rotary hoolradapted to take a loop of needle thread and carry it about the bobbin case, a roclr shaft having a finger ex-V tending therefrom and normally engaging said nose to hold the bobbin case from rotation, an arm rigid with the rock shaft, a cam on the driving shaft engaging said arm and operating to hold the linger in operative position during avconsiderable portion of the rotation of the hook and to periodically withdraw the arm from the nose to allow a loop of needle thread to pass the latter, and a stationary positioning finger cooperating with the shoulder of the bobbin case to prevent rotation of the latter while the loop of needle thread is passing the nose.

'3. In a sewing machine, the combination with a bed plate, of a driving shaft situated beneath said bed plate, a second shaft geared to the driving shaft, a hook rotated by the second shaft, a bobbin case about which the hook rotates and which is provided with a nose and a shoulder, a rock shaft having a finger normally engaging the nose and preventing the bobbin case from rotation, a stationary positioning finger co-operating with the shoulder but normally spaced thereclearance space for the loop of needle thread from to provide clearance space for the to pass the latter2 the stationary positioning l0 needle loop to pass and a cam member on the finger at such time co-operating With the driving shaft for holding the nger in op shoulder to prevent rotation of the bobbin ceratve position during a considerable porcase.

tion of the rotation of the hook and for In testimony whereof, I have signed my periodically rocking the rock shaft and Withname to this specification.

drawing the inger from the nose to provide p JOHN KIEWICZ. 

